Led package

ABSTRACT

An exemplary encapsulation structure for encapsulating an LED chip includes a first encapsulation, a second encapsulation and a transparent resin layer with phosphorous compounds doped therein. The first encapsulation defines a receiving room for receiving the LED chip therein. The second encapsulation defines a receiving space for receiving the first encapsulation therein. The second encapsulation is separated from the first encapsulation to define a clearance between the first encapsulation and the second encapsulation. The transparent resin layer is filled in the clearance. The transparent resin layer has a uniform thickness.

BACKGROUND

1. Technical Field

The present disclosure relates to semiconductor packages, andparticularly to an LED (light emitting diode) package with a highuniformity of light illumination.

2. Description of the Related Art

A typical LED package includes a substrate, an LED chip disposed on thesubstrate and an encapsulation material encapsulating the LED chip. Theencapsulation material includes a resin and phosphorous compounds dopedwithin the resin, which are configured to turn a portion of lightemitted from the LED chip into a light with a different color. The lightwith a different color and the other portion of the light from the LEDchip are mixed together to obtain a light with a desired color.

However, the encapsulation material is usually curved and has differentthickness, and the phosphorous compounds in the resin are usuallyunevenly distributed, which result in that the center of the commonlyused LED package has a higher light intensity than the circumference.The non-uniformity of light illumination of the LED package will causeunfavorable effects on the usage of LED package. Therefore, it isdesirable to provide an LED package which can overcome the describedlimitations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section of an LED package in accordance with a firstexemplary embodiment of present disclosure, wherein the LED packageincludes a substrate, an LED chip mounted on the substrate and anencapsulation structure encapsulating the LED chip.

FIG. 2 is a bottom view of the encapsulation structure of the LEDpackage of FIG. 1.

FIG. 3 is a schematic view for showing a method of manufacturing thecapsulation of the LED package of FIG. 1.

FIG. 4 is a cross section of an LED package in accordance with a secondexemplary embodiment of present disclosure.

DETAILED DESCRIPTION

Embodiments of an LED package as disclosed are described in detail herewith reference to the drawings.

Referring to FIG. 1, an LED package 10 according to a first embodimentis shown. The LED package 10 includes a substrate 11, an LED chip 12mounted on the substrate 11 and an encapsulation structure 17 enclosingthe LED chip 12.

The substrate 11 is made of thermally conductive and electricallyinsulating material such as epoxy, silicone, silicon oxide or a mixturethereof. The substrate 11 includes a main plate 118, and a firstsoldering pad 116 and a second soldering pad 117 mounted at two oppositesides of a bottom surface 111 of the main plate 118, respectively. Inaddition to the bottom surface 111, the main plate 118 further has a topsurface 110 opposite to the bottom surface 111. A first locating hole114 and a second locating hole 115 are defined in the main plate 118 ofthe substrate 11. Each of the first locating hole 114 and the secondlocating hole 115 extends through the main plate 118 of the substrate 11along a height direction thereof, from the top surface 110 to the bottomsurface 111. Each of the first soldering pad 116 and the secondsoldering pad 117 is flat. The first soldering pad 116 and the secondsoldering pad 117 are formed on the bottom surface 111 of the main plate118 of the substrate 11 and separated from each other.

The LED chip 12 includes a first electrode 121 and a second electrode122 located at two opposite sides of a top face thereof. The LED chip 12is mounted on the substrate 11 with a bottom face thereof contacting thetop surface 110 of the main plate 118 of the substrate 11.

The encapsulation structure 17 is made of transparent material orsemi-transparent material. The encapsulation structure 17 includes afirst encapsulation 13, a second encapsulation 18 spaced apart from thefirst encapsulation 13, a first electric connecting unit electricallyconnected between the first electrode 121 and the first soldering pad116, a second electric connecting unit electrically connected betweenthe second electrode 122 and the second soldering pad 117, and atransparent resin layer 172 located between and interconnecting thefirst encapsulation 13 and the second encapsulation 18.

The first encapsulation 13 includes an annular first planar mountingsurface 131 facing and adjacent to the substrate 11, a first convexlight exit surface 132 connected to an outer periphery of the firstmounting surface 131 and a first light incident surface 134 connected toan inner periphery of the first mounting surface 131. The first lightincident surface 134 is concaved from the inner periphery of the firstmounting surface 131 towards the first light exit surface 132. Arectangular receiving room 133 surrounded by the first light incidentsurface 134 is defined in a middle of the first encapsulation 13.

The second encapsulation 18 has a configuration similar to that of thefirst encapsulation 13 but has a size larger than that of the firstencapsulation 13. The second encapsulation 18 encloses the firstencapsulation 13. More specifically, the second encapsulation 18includes an annular second planar mounting surface 181 facing andadjacent to the substrate 11, a second convex light exit surface 182connected to an outer periphery of the second mounting surface 181 and asecond light incident surface 184 connected to an inner periphery of thesecond mounting surface 181. The second light incident surface 184 isconcaved from the inner periphery of the second mounting surface 181towards the second light exit surface 182. A receiving space 183surrounded by the second light incident surface 184 is defined in amiddle of the second encapsulation 18. The receiving space 183 has acylindrical lower portion and a doomed upper portion.

The first encapsulation 13 is received in the receiving space 183 of thesecond encapsulation 18, with the first light exit surface 132 facingand spaced from the second light incident surface 184 of the secondencapsulation 18 to define a clearance 171 therebetween. The transparentresin layer 172 is filled in the clearance 171. The transparent resinlayer 172 consists of a sleeve-shaped body and a doomed roof over thebody, and has a uniform thickness. A bottom side of the transparentresin layer 172 is annular. The transparent resin layer 172 includesfluorescent powder, such as YAG, TAG, silicate, nitride, nitrogenoxides, phosphide or sulfide evenly distributed in an interior thereof.The fluorescent powder is used for changing color of a portion of lightfrom the LED chip 12 into a different color.

The first mounting surface 131 of the first encapsulation 13, the secondmounting surface 181 of the second encapsulation 18 and the bottom sideof the transparent resin layer 172 have a common center and are coplanarto each other, to cooperatively form a planar mounting surface 173 ofthe encapsulation 17. Alternatively, the bottom side of the transparentresin layer 172 can be any other closed shape, such as annularrectangle, ellipse, etc, for surrounding the LED chip 12 at a centerthereof.

The first electric connecting unit includes a first electric pole 135, afirst electric conduction block 139 received in a top end of the firstlocating hole 114 and a transparent first electric conduction layer 137interconnecting the first electric pole 135 and the first electricconduction block 139. Similarly, the second electric connecting unitincludes a second electric pole 136, a second electric conduction block130 received in a top end of the second locating hole 115 and a secondelectric conduction layer 138 interconnecting the second electric pole136 and the second electric conduction block 130. The first electricconduction layer 137 and the second electric conduction layer 138 areboth made of transparent and electrically conductive material, such astransparent metal, indium tin oxide or carbon nano-tubes. The firsttransparent conductive layer 137 and the second transparent layer 138can be formed on the first capsulation 13 and the second capsulation 18by electroplating, chemical plating, sputtering, electron beamevaporation or other related known methods.

The encapsulation structure 17 is mounted on the substrate 11 via themounting surface 173 connecting the top surface 110 of the substrate 11.A hermetical material 16 is filled in an outer portion of a clearancedefined between the mounting surface 173 of the capsulation 17 and thetop surface 110 of the substrate 11. The hermetical material 16 enclosesthe LED chip 12 for sealing the LED chip 12 between the capsulation 17and the substrate 11.

A first electric conduction post 112 is received in a bottom end of thefirst locating hole 114 of the substrate 11 for electricallyinterconnecting the first electric conduction block 139 of theencapsulation structure 17 and the first soldering pad 116 of thesubstrate 11. A second electric conduction post 113 is received in abottom end of the second locating hole 117 of the substrate 11 forelectrically interconnecting the second electric conduction block 130 ofthe encapsulation structure 17 and the second soldering pad 117 of thesubstrate 11. The first and second electric conduction posts 112, 113are formed by filling electrically conductive material in the first andsecond locating holes 114, 115 from a bottom side of the substrate 11after the first electric conduction block 139 and the second electricconduction block 130 are interferentially inserted into the top ends ofthe first locating hole 114 and the second locating hole 115,respectively.

The LED chip 12 is received in the receiving room 133 of the firstencapsulation 13 and spaced apart from the first light incident surface134 of the first encapsulation 13 to define a space 15 therebetween. Thefirst electric pole 135 of the capsulation 17 is aligned with andconnects the first electrode 121 of the LED chip 12 via eutecticbonding. The second electric pole 136 of the capsulation 17 is alignedwith and connects the second electrode 122 of the LED chip 12 viaeutectic bonding. A first insulation layer 141 is located between thefirst electric conduction layer 137 and a corresponding side of the LEDchip 12 which is adjacent to the first conduction layer 137. A secondinsulation layer 142 is located between the second electric conductionlayer 138 and a corresponding side of the LED chip 12 which is adjacentto the second conduction layer 138.

During operation, light emitted from the LED chip 12 travels through thefirst encapsulation 13, the transparent resin layer 172 and the secondencapsulation 18 in sequence, and finally exits the LED package 10 viathe second light exit surface 182 of the second encapsulation 18. Due tothe thickness of the transparent resin layer 172 sandwiched between thefirst encapsulation 13 and the second encapsulation 18 is uniform, andthe fluorescent powder evenly disturbed in the transparent resin layer172 has a uniform density, the light illuminated by the LED package 10can have a higher uniformity. In addition, due to the fact that thefirst encapsulation 13 is located between the LED chip 12 and thetransparent resin layer 172, heat generated by the LED chip 12 is notdirectly absorbed by the fluorescent powders which are contained in thetransparent resin layer 172, thereby enabling the fluorescent powders tohave a longer time of use since the speed of degradation of thefluorescent powders due to the heat of the LED chip 12 is significantlylowered.

Furthermore, due to the fact that the encapsulation structure 17includes the first electric pole 135 and the second electric pole 136formed thereon, and the first electric pole 135 and the second electricpole 136 respectively directly connect the first electrode 121 and thesecond electrode 122 of the LED chip 12, gold wires are not needed inthe LED package 10 according to the present disclosure. Thus, glue forconnecting the gold wires and the electrodes of the LED chip together isalso not needed during the manufacture of the LED package 10, wherebythe LED package 10 can have a low manufacture cost and a highmanufacture efficiency. Moreover, the first electric pole 135 and thesecond electric pole 136 of the encapsulation structure 17 and the firstelectrode 121 and the second electrode 122 of the LED chip 12 areconnected together via eutectic bonding, which can provide improvedworking stability and reliability of the LED package 10.

Referring to FIG. 3, a method for manufacturing the capsulationstructure 17 of the LED package 10 according to a first exemplaryembodiment is shown. The method includes following steps:

The first step is to provide the first encapsulation 13 and the secondencapsulation 18.

The second step is to provide a mounting tablet 175 having an entrance174 and a vent 177. A distance defined between the entrance 174 and thevent 177 is substantially equal to an outer diameter of the firstmounting surface 131 of the first encapsulation 13. The firstencapsulation 13 and the second encapsulation 18 are mounted on asupporting surface 178 of the mounting tablet 175 with a clearance 171defined therebetween communicating with the entrance 174 and the vent177 of the mounting tablet 175. The clearance 171 is defined between thefirst light exit surface 132 of the first encapsulation 13 and thesecond light incident surface 134 of the second encapsulation 18.

The third step is to provide a liquid transparent resin 174 withphosphorous compounds evenly distributed therein, and inject the liquidtransparent resin 174 into the clearance 171 via the entrance 174 of themounting tablet 175. The vent 177 is for air discharging from theclearance 171 when the liquid transparent resin 174 is injected into theclearance 171. Thereafter, the liquid transparent resin 174 is held inthe clearance 171 until it is solidified to form the transparent resinlayer 172.

Referring to FIG. 4, an LED package 20 according to a second exemplaryembodiment is shown. The LED package 20 includes a substrate 21, an LEDchip 22 and an encapsulation structure 27.

The substrate 21 includes a main plate 218, and a first soldering pad216 and a second soldering pad 217 mounted at two opposite sides of themain plate 218, respectively. The main plate 218 of the substrate 21includes a top surface 210 and a bottom surface 211 opposite to the topsurface 210. A locating hole 214 extends through the main plate 218 ofthe substrate 21 along a height direction of the main plate 218 from thetop surface 210 to the bottom surface 211.

The first soldering pad 216 is flat, and directly formed on the bottomsurface 211 of the main plate 218 of the substrate 21. The firstsoldering pad 216 seals a bottom end of the locating hole 214. Thesecond soldering pad 217 is substantially U-shaped, and has a firstsection contacting the top surface 210 of the main plate 218 of thesubstrate 21, a second section contacting a side surface of the mainplate 218 of the substrate 21 and a third section contacting the bottomsurface of the main plate 218 of the substrate 21. The first solderingpad 216 and the second soldering pad 217 are separated from each other.

The LED chip 22 includes a first electrode 221 located at a top sidethereof and a second electrode 222 located at a bottom side thereof. TheLED chip 22 is mounted over the top surface 210 of the main plate 218 ofthe substrate 21, with the second electrode 222 directly connecting atop surface of the first section of the second soldering pad 217. Thesecond electrode 222 of the LED chip 22 is electrically connected withthe second soldering pad 217 of the substrate 21 by soldering.

The encapsulation structure 27 is similar to the encapsulation structure17 of the LED package 10 of first exemplary embodiment; the differencebetween the encapsulation structure 27 and the encapsulation structure17 is that: the encapsulation structure 27 includes only one electricalconnecting unit. The electrical connecting unit includes an electricpole 235 located at a middle portion of the light incident surface 234,an electric conduction block 239 interferentially received in a top endof the locating hole 214 of the substrate 21, and a transparent electricconduction layer 237 interconnecting the electric pole 235 and theelectric conduction block 239. The electrical connecting unit iselectrically connected between the first electrode 221 of the LED chip22 and the first soldering pad 216 of the substrate 21 via an electricalconduction post 212.

It is to be further understood that even though numerous characteristicsand advantages have been set forth in the foregoing description ofembodiments, together with details of the structures and functions ofthe embodiments, the disclosure is illustrative only; and that changesmay be made in detail, especially in matters of shape, size, andarrangement of parts within the principles of the disclosure to the fullextent indicated by the broad general meaning of the terms in which theappended claims are expressed.

1. An encapsulation structure for encapsulating an LED chip, comprising:a first encapsulation defining a receiving room for receiving the LEDchip therein; a second encapsulation defining a receiving spacereceiving the first encapsulation therein, the second encapsulationspaced from the first encapsulation to define a clearance therebetween;and a transparent resin layer with phosphorous compounds doped thereinbeing filled in the clearance, the transparent resin layer having auniform thickness.
 2. The encapsulation structure of claim 1, whereinthe first encapsulation comprises an annular first mounting surface, afirst light exit surface connected to an outer periphery of the firstmounting surface and a first light incident surface connected to aninner periphery of the first mounting surface, the first light incidentsurface concaved from the inner periphery of the first mounting surfacetowards the first light exit surface to define the receiving roomenclosed by the first light incident surface.
 3. The encapsulationstructure of claim 2, wherein the second encapsulation comprises anannular second mounting surface, a second light exit surface connectedto an outer periphery of the second mounting surface and a second lightincident surface connected to an inner periphery of the second mountingsurface, the second light incident surface concaved from the innerperiphery of the second mounting surface towards the second light exitsurface to define the receiving space enclosed by the second lightincident surface, the first mounting surface and the second mountingsurface being coplanar to each other.
 4. The encapsulation structure ofclaim 3, wherein the clearance is defined between the first light exitsurface and the second light incident surface.
 5. The encapsulationstructure of claim 3, wherein a bottom side of the transparent resinlayer is annular.
 6. The encapsulation structure of claim 3, wherein thefirst mounting surface, a bottom side of the transparent resin layer andthe second mounting surface have a common center and are coplanar toeach other.
 7. An LED package, comprising: a substrate; an LED chipmounted on the substrate; and an encapsulation structure mounted on thesubstrate and encapsulating the LED chip therein, the encapsulationcomprising: a first encapsulation defining a receiving room receivingthe LED chip therein; a second encapsulation defining a receiving spacereceiving the first encapsulation therein, the second encapsulationspaced from the first encapsulation to define a clearance between thefirst encapsulation and the second encapsulation; and a transparentresin layer with phosphorous compounds doped therein being filled in theclearance, the transparent resin layer having a uniform thickness. 8.The LED package of claim 7, wherein each of the first and secondencapsulations comprises a light incident surface at one side thereofadjacent to the substrate and a light exit surface at another sidethereof far away from the substrate, the clearance being defined betweenthe light exit surface of the first encapsulation and the light incidentsurface of the second encapsulation.
 9. The LED package of claim 8,wherein each of the first and second encapsulations further comprises anannular mounting surface, the mounting surfaces of the first and secondencapsulations being coplanar to each other.
 10. The LED package ofclaim 7, wherein a bottom side of the transparent resin layer isannular, the mounting surface of the first encapsulation, the mountingsurface of the second encapsulation and the bottom side of thetransparent resin layer have a common center and are coplanar to eachother.
 11. The LED package of claim 8, wherein the light exit surface ofeach of the first and second encapsulations connects an outer peripheryof a corresponding mounting surface, the light incident surface of eachof the first and second encapsulations concaved from an inner peripheryof a corresponding mounting surface towards a corresponding light exitsurface.
 12. The LED package of claim 7, wherein the LED chip comprisestwo electrodes located at a top side thereof, the encapsulationcomprising two electric poles aligned with and connecting the twoelectrodes of the LED chip, respectively.
 13. The LED package of claim12, wherein the substrate defines two locating holes and comprises twosoldering pads sealed bottom sides of the two locating holes,respectively, the encapsulation further comprising two electricconduction blocks received in the locating holes of the substrate,respectively, and two electric conduction layers each interconnecting acorresponding electric pole and a corresponding electric conductionblock, each of the electric conduction blocks electrically connected toa corresponding soldering pads via an electric post.
 14. The LED packageof claim 7, wherein the LED chip comprises a first electrode and asecond electrode located at two opposite sides, respectively, theencapsulation comprising an electric pole aligned with and connected tothe first electrode of the LED chip.
 15. The LED package of claim 14,wherein the substrate comprises a first soldering pad and a secondsoldering pad separately from each other and a locating hole definedtherein, the first soldering pad sealed a bottom side of the locatinghole, the encapsulation further comprising an electric conduction blockreceived in the locating hole and an electric conduction layerinterconnecting the electric pole and the electric conduction block, theelectric conduction block electrically connected the first soldering padvia an electric post, the LED chip mounted on the substrate with thesecond electrode directly connected to the second soldering pad.
 16. Amethod of manufacturing an encapsulation structure for encapsulating anLED chip, comprising: providing a first encapsulation defining areceiving room for receiving the LED chip therein and a secondencapsulation defining a receiving space for receiving the firstencapsulation therein; providing a mounting tablet defining an entrancetherein, mounting the first encapsulation and the second encapsulationon the mounting tablet with a clearance defined therebetweencommunicating with the entrance; injecting a liquid transparent resinwith phosphorous compounds disturbed therein into the clearance via theentrance; and solidifying the liquid transparent resin to form atransparent resin layer interconnecting the first encapsulation and thesecond encapsulation.
 17. The method of claim 16, wherein the mountingtablet further defines a vent therein, the vent communicated with theclearance when the first encapsulation and the second encapsulation aremounted on the mounting tablet.